1. Field of the Invention
The present application relates to novel substituted dihydropyrazolone derivatives, processes for their preparation, their use for treatment and/or prophylaxis of diseases and their use for the preparation of medicaments for treatment and/or prophylaxis of diseases, in particular cardiovascular and haematological diseases and kidney diseases, and for promoting wound healing.
2. Background of the Invention
A deficient supply of oxygen to the human organism or its components which either impairs regular functioning of the organism or its components due to its duration and/or its extent or causes its functioning to break down completely is called hypoxia. Hypoxia can be caused by a reduction in the available oxygen in the air breathed in (for example during periods at a high altitude), by disorders in external respiration (for example as a result of disturbed functioning of the lungs or obstruction of the respiratory tract), by a reduction in the cardiac output (for example in the event of cardiac insufficiency, acute right ventricular overloading with pulmonary embolism), by too low an oxygen transport capacity of the blood (for example as a result of an anaemia or intoxication, for example with carbon monoxide), locally demarcated by a reduced blood flow as a result of vascular occlusions (ischaemia states typically for example of the heart, the lower extremities or the brain, diabetic macro- and microangiopathy) or also by an increased oxygen requirement of the tissue (for example as a result of increased muscular activity or local inflammations) [Eder, Gedigk (ed.), Allgemeine Pathologie und pathologische Anatomie, 33rd ed., Springer Verlag, Berlin, 1990]
The human organism is capable to a limited extent of adapting acutely and chronically to situations of reduced oxygen supply. In addition to an immediate response, which includes inter alia an increase in the cardiac output and respiratory output and a local dilation of blood vessels by vegetative-nervous control mechanisms, hypoxia brings about a change in the transcription of numerous genes. The function of the gene products here serves to compensate the oxygen deficiency. Thus, expression of several enzymes of glycolysis and glucose transporter 1 is enhanced, as a result of which anaerobic ATP production increases and survival of the oxygen deficiency is rendered possible [Schmidt, Thews (ed.), Physiologie des Menschen, 27th ed., Springer Verlag, Berlin, 1997; Löffler, Petrides (ed.), Biochemie und Pathobiochemie, 7th ed., Springer Verlag, Berlin, 2003].
Hypoxia furthermore leads to enhanced expression of vascular endothelial cell growth factor, VEGF, as a result of which regeneration of blood vessels (angiogenesis) is stimulated in hypoxic tissues. The blood flow through ischaemic tissue is thereby improved in the long term. This counter-regulation is evidently only very inadequate in the case of various cardiovascular diseases and vascular occlusion diseases [overview in: Simons and Ware, Therapeutic angiogenesis in cardiovascular disease, Nat. Rev. Drug. Discov. 2 (11), 863-71 (2003)].
Furthermore, in cases of systemic hypoxia expression of the peptide hormone erythropoietin formed predominantly in the interstitial fibroblasts of the kidneys is enhanced. The formation of red blood cells in the bone marrow is thereby stimulated, and the oxygen transport capacity of the blood is therefore increased. This effect has been and is used by high-performance athletes in so-called high altitude training. A decrease in the oxygen transport capacity of the blood for example as a result of anaemia after hemorrhaging usually causes an increase in erythropoietin production in the kidney. With certain forms of anaemia, this regulatory mechanism may be disturbed or its normal value may be set lower. Thus for example in patients suffering from renal insufficiency, erythropoietin is indeed produced in the kidney parenchyma, but in significantly reduced amounts with respect to the oxygen transport capacity of the blood, which results in so-called renal anaemia. Renal anaemia in particular, but also anemias caused by tumours and HIV infection are conventionally treated by parenteral administration of recombinant human erythropoietin (rhEPO). No alternative therapy with an orally available medicament currently exists for this expensive therapy [overview in: Eckardt, The potential of erythropoietin and related strategies to stimulate erythropoiesis, Curr. Opin. Investig. Drugs 2(8), 1081-5 (2001); Berns, Should the target hemoglobin for patients with chronic kidney disease treated with erythropoietic replacement therapy be changed?, Semin. Dial. 18 (1), 22-9 (2005)]. Recent studies demonstrate that, in addition to its erythropoiesis-increasing action, erythropoietin also has a protective (anti-apoptotic) action, which is independent thereof, on hypoxic tissue, in particular the heart and the brain.
Furthermore, according to recent studies therapy with erythropoietin reduces the average severity of morbidity in patients with cardiac insufficiency [overviews in: Caiola and Cheng, Use of erythropoietin in heart failure management, Ann. Pharmacother. 38 (12), 2145-9 (2004); Katz, Mechanisms and treatment of anemia in chronic heart failure, Congest. Heart. Fail. 10 (5), 243-7 (2004)].
The genes described above which are induced by hypoxia have the common feature that the increase in their expression under hypoxia is caused by the so-called hypoxia-inducible transcription factor (HIF). HIF is a heterodimeric transcription factor which comprises an alpha and a beta subunit. Three HIF alpha isoforms have been described, of which HIF-1 alpha and HIF-2 alpha are highly homologous and are of importance for hypoxia-induced gene expression. While the beta subunit (of which 2 isoforms have been described), which is also called ARNT (aryl hydrocarbon receptor nuclear translocator), is expressed constitutively, expression of the alpha subunit depends on the oxygen content in the cell. Under normoxia, the HIF alpha protein is poly-ubiquitinized and then degraded proteasomally. Under hypoxia this degradation is inhibited, so that HIF alpha dimerizes with ARNT and can activate its target genes. The HIF dimer bonds here to so-called hypoxia-responsible elements (HRE) in the regulatory sequences of its target genes. The HRE are defined by a consensus sequence. Functional HRE have been detected in the regulatory elements of numerous hypoxia-induced genes [overviews in: Semenza, Hypoxia-inducible factor 1: oxygen homeostasis and disease pathophysiology, Trends Mol. Med. 7 (8), 345-50 (2001); Wenger and Gassmann, Oxygen(es) and the hypoxia-inducible factor-1, Biol. Chem. 378 (7), 609-16 (1997)].
The molecular mechanism on which this regulation of HIF alpha is based has been clarified by the works of several independent groups of researchers. The mechanism is conserved from species to species: HIF alpha is hydroxylated by a subclass of oxygen-dependent prolyl 4-hydroxylases, called PHD or EGLN, on two specific prolyl radicals (P402 and P564 of the human HIF-1 alpha subunit). The HIF prolyl 4-hydroxylases are iron-dependent, 2-oxoglutarate-converting dioxygenases [Epstein et al., C. elegans EGL-9 and mammalian homologs define a family of dioxygenases that regulate HIF by prolyl hydroxylation, Cell 107 (1), 43-54 (2001); Bruick and McKnight, A conserved family of prolyl-4-hydroxylases that modify HIF, Science 294 (5545), 1337-40 (2001); Ivan et al., Biochemical purification and pharmacological inhibition of a mammalian prolyl hydroxylase acting on hypoxia-inducible factor, Proc. Natl. Acad. Sci. U.S.A. 99 (21), 13459-64 (2002)]. The enzymes were annotated as prolyl hydroxylases for the first time in 2001 [Aravind and Koonin, The DNA-repair protein AlkB, EGL-9, and leprecan define new families of 2-oxoglutarate- and iron-dependent dioxygenases, Genome Biol. 2 (3), research0007.1-0007.8, Epub 2001 Feb. 19].
The pVHL tumour suppressor protein, which together with elongin B and C forms the so-called VBC complex, which adapts the HIF alpha subunit to an E3 ubiquitin ligase, bonds to the prolyl-hydroxylated HIF alpha subunit. Since the prolyl 4-hydroxylation of the HIF alpha subunit and its subsequent degradation takes place as a function of the intracellular concentration of oxygen, HIF prolyl 4-hydroxylases have also been called a cellular oxygen sensor. Three isoforms of these enzymes have been identified: EGLN1/PHD2, EGLN2/PHD1 and EGLN3/PHD3. Two of these enzymes (EGLN2/PHD1 and EGLN3/PHD3) are induced transcriptionally even under hypoxia and are possibly responsible for the lowering of the HIF alpha levels to be observed under chronic hypoxia [overview in: Schofield and Ratcliffe, Oxygen sensing by HIF hydroxylases, Nat. Rev. Mol. Cell. Biol. 5 (5), 343-54 (2004)].
Selective pharmacological inhibition of HIF prolyl 4-hydroxylases brings about the increase in the gene expression of HIF-dependent target genes and is therefore beneficial for the therapy of numerous disease syndromes. In the case of diseases of the cardiovascular system in particular, an improvement in the course of the diseases is to be expected from induction of new blood vessels and the change in the metabolic situation of ischaemic organs from aerobic to anaerobic ATP production. An improvement in the vascularization of chronic wounds promotes the healing process, especially in the case of poorly healing ulcera cruris and other chronic skin wounds. The induction of endogenous erythropoietin in certain disease forms, in particular in patients with renal anaemia, is likewise a therapeutic goal to be aimed for.
The HIF prolyl 4-hydroxylase inhibitors described hitherto in the scientific literature do not meet the requirements to be imposed on a medicament. These are either competitive oxoglutarate analogues (such as for example N-oxalylglycine), which are characterized by their very low action potency, and therefore in in vivo models have as yet shown no action in the sense of an induction of HIF target genes. Or they are iron-complexing agents (chelators), such as desferroxamine, which act as non-specific inhibitors of iron-containing dioxygenases and, although they bring about an induction of the target genes, such as for example erythropoietin, in vivo, evidently counteract erythropoiesis by complexing of the available iron.
2-Heteroaryl-4-aryl-1,2-dihydropyrazolones having a bactericidal and/or fungicidal action are disclosed in EP 165 448 and EP 212 281. The use of 2-heteroaryl-4-aryl-1,2-dihydropyrazolones as lipoxygenase inhibitors for treatment of respiratory tract, cardiovascular and inflammatory diseases is claimed in EP 183 159. 2,4-Diphenyl-1,2-dihydropyrazolones having a herbicidal activity are described in DE 2 651 008. The preparation and pharmacological properties of certain 2-pyridyl-1,2-dihydropyrazolones are reported in Helv. Chim. Acta 49 (1), 272-280 (1966). WO 96/12706, WO 00/51989 and WO 03/074550 claim compounds having a dihydropyrazolone partial structure for treatment of various diseases, and hydroxy- or alkoxy-substituted bipyrazoles for treatment of neuropsychiatric diseases are disclosed in WO 2006/101903. Heteroaryl-substituted pyrazole derivatives for treatment of pain and various CNS diseases are furthermore described in WO 03/051833 and WO 2004/089303. WO 2006/114213 has meanwhile disclosed 2,4-dipyridyl-1,2-dihydropyrazolones as inhibitors of HIF prolyl 4-hydroxylases.
The X-ray crystal structure of the compound 3-methyl-1-(pyridin-2-yl)-4-(1-pyridin-2-yl-3-methyl-1H-pyrazol-5-yl)-2H-3-pyrazolin-5(1H)-one (other name: 5,5′-dimethyl-2,2′-dipyridin-2-yl-1′,2′-dihydro-2H,3′H-3,4′-bipyrazol-3′-one) is reported in Acta Crystallogr., Section E: Structure Reports Online E57 (11), o1126-o1127 (2001) [Chem. Abstr. 2001:796190]. The synthesis of certain 3′,5-dimethyl-2-phenyl-1′-(1,3-thiazol-2-yl)-1′H,2H-3,4′-bipyrazol-5′-ol derivatives is described in Indian J. Heterocyclic Chem. 3 (1), 5-8 (1993) [Chem. Abstr. 1994:323362]. The preparation and tautomerism of individual 4-(pyrazol-5-yl)pyrazolin-5-one derivatives is reported in J. Heterocyclic Chem. 27 (4), 865-870 (1990) [Chem. Abstr. 1991:428557]. A therapeutic use has not hitherto been described for the compounds mentioned in these publications. The compound 2-tert-butyl-1′-[4-(4-chlorophenyl)-1,3-thiazol-2-yl]-3′,5-dimethyl-1′H,2H-3,4′-bipyrazol-5′-ol is listed as a test example in WO 2007/008541.